diff --git a/__test__/Polyline/__snapshots__/offset.test.ts.snap b/__test__/Polyline/__snapshots__/offset.test.ts.snap
index 1379bcec8..22b0c818b 100644
--- a/__test__/Polyline/__snapshots__/offset.test.ts.snap
+++ b/__test__/Polyline/__snapshots__/offset.test.ts.snap
@@ -310,3 +310,21 @@ Array [
   ],
 ]
 `;
+
+exports[`简单图形因为点在线内算法错误导致的丢失 1`] = `8.675026988029915`;
+
+exports[`简单图形因为点在线内算法错误导致的丢失 2`] = `8.252659494518674`;
+
+exports[`简单图形因为点在线内算法错误导致的丢失 3`] = `6.802593049888034`;
+
+exports[`简单图形因为点在线内算法错误导致的丢失 4`] = `6.045525633131274`;
+
+exports[`闭合多段线判断精度和重复交点参数导致偏移丢失 1`] = `54789.14760701891`;
+
+exports[`闭合多段线判断精度和重复交点参数导致偏移丢失 2`] = `54907.17933624483`;
+
+exports[`闭合多段线判断精度和重复交点参数导致偏移丢失 3`] = `55497.39792073307`;
+
+exports[`闭合多段线判断精度和重复交点参数导致偏移丢失 4`] = `56678.13326318633`;
+
+exports[`闭合多段线判断精度和重复交点参数导致偏移丢失 5`] = `57859.26303559798`;
diff --git a/__test__/Polyline/offset.test.ts b/__test__/Polyline/offset.test.ts
index 9cff50ee8..e18f0d4cc 100644
--- a/__test__/Polyline/offset.test.ts
+++ b/__test__/Polyline/offset.test.ts
@@ -777,3 +777,40 @@ test('土偏移因为点在圆弧切线上错误导致的丢失', () =>
     cus = pl.GetOffsetCurves(801);
     expect(cus.length).toBe(1);
 });
+
+//ISSUE #IKSMH
+test('闭合多段线判断精度和重复交点参数导致偏移丢失', () =>
+{
+    let f = new CADFile();
+    f.Data =
+        [1, ["Polyline", 1, 1, 3, false, 7, -1, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0.042016806722689815, 0.028011204481792618, 0, 1], 2, 11, [15758.920914649752, -1642.832074394305], 1.1432358165627696, [15758.920914649756, -3551.5797508523133], 0.010240353549940432, [20850.68748853413, -2761.478041111637], 0.39873042440013945, [23564.17781148077, 901.7338948663096], 0.029927117999965277, [22452.27083112051, 6973.8467189556395], 0, [31778.947378692996, 6973.846718955635], 0, [31327.636369627562, 7575.594679533537], 0, [31646.066893308867, 7787.881806674935], 0, [20955.832135358123, 7787.881806674936], 0, [21703.795934364476, 5637.485884531684], -0.559029831351755, [15758.920914649752, -1642.832074394304], 0, false]]
+
+    f.Read();
+    let pl = f.ReadObject() as Polyline;
+
+    for (let d of [40, 50, 100, 200, 300])
+    {
+        let cus = pl.GetOffsetCurves(d);
+
+        expect(cus.length).toBe(1);
+        expect(cus[0].Length).toMatchSnapshot();
+    }
+});
+//ISSUE #IKSMH
+test('简单图形因为点在线内算法错误导致的丢失', () =>
+{
+    let f = new CADFile();
+    f.Data =
+        [1, ["Polyline", 1, 1, 3, false, 7, -1, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, -0.01400560224089542, 0.37815126050420145, 0, 1], 2, 7, [2.075848303393214, 0.09193367302761479], -3.109533447960064, [2.8332320619106284, 1.1077844311377247], 0, [3.542914171656688, 1.1077844311377247], 0, [3.542914171656688, -0.4890219560878247], 0, [2.0758483033932134, -0.4890219560878247], 0, [2.0758483033932134, -0.4890219560878247], 0, [2.0758483033932134, 0.09193367302761501], 0, false]]
+
+    f.Read();
+    let pl = f.ReadObject() as Polyline;
+
+    for (let d of [0.2, 0.3, 0.4, 0.5])
+    {
+        let cus = pl.GetOffsetCurves(d);
+
+        expect(cus.length).toBe(1);
+        expect(cus[0].Length).toMatchSnapshot();
+    }
+});
diff --git a/src/DatabaseServices/PointInPolyline.ts b/src/DatabaseServices/PointInPolyline.ts
index b3e4bf2a7..3db858a96 100644
--- a/src/DatabaseServices/PointInPolyline.ts
+++ b/src/DatabaseServices/PointInPolyline.ts
@@ -1,5 +1,5 @@
 import { Vector2, Vector3 } from 'three';
-import { angle, equaln } from '../Geometry/GeUtils';
+import { angle, equaln, equal } from '../Geometry/GeUtils';
 import { IntersectOption } from '../GraphicsSystem/IntersectWith';
 import { Arc } from './Arc';
 import { Line } from './Line';
@@ -108,33 +108,45 @@ export function IsPointInPolyLine(pl: Polyline, pt: Vector3): boolean
         }
         else //圆弧
         {
-            let arc = pl.GetCurveAtIndex(i);
+            let arc = pl.GetCurveAtIndex(i) as Arc;
             let sp = arc.StartPoint;
             let ep = arc.EndPoint;
 
-            //当点和起点或者终点和点相切时
-            if (equaln(sp.x, pt.x) && sp.y > pt.y)
+            //如果相切
+            if (equaln(Math.abs(pt.x - arc.Center.x), arc.Radius))
             {
-                let der = arc.GetFistDeriv(0);
-                if (equaln(der.x, 0))
+                //当点和起点或者终点和点相切时
+                if (equaln(sp.x, pt.x) && sp.y > pt.y)
                 {
-                    if (ep.x - sp.x < 0) crossings++;
-                    continue;
+                    if (ep.x - sp.x < -1e-5)
+                        crossings++;
+                }
+                else if (equaln(ep.x, pt.x) && ep.y > pt.y)
+                {
+                    if (ep.x - sp.x > 1e-5)
+                        crossings++;
                 }
+                continue;
+            }
+
+            if (equaln(sp.x, pt.x) && sp.y > pt.y)
+            {
+                let der = arc.GetFistDeriv(0);
+                if (der.x < -1e-5)
+                    crossings++;
             }
             if (equaln(ep.x, pt.x) && ep.y > pt.y)
             {
                 let der = arc.GetFistDeriv(1);
-                if (equaln(der.x, 0))
-                {
-                    if (ep.x - sp.x > 0) crossings++;
-                    continue;
-                }
+                if (der.x > 1e-5)
+                    crossings++;
             }
+
             for (let pti of arc.IntersectWith(insLine, IntersectOption.ExtendArg))
             {
-                if (pti.y < pt.y)
+                if (pti.y < pt.y || equal(sp, pti) || equal(ep, pti))
                     continue;
+
                 let der = arc.GetFistDeriv(pti);
                 if (!equaln(der.x, 0)) //相切.
                     crossings++;
diff --git a/src/DatabaseServices/Polyline.ts b/src/DatabaseServices/Polyline.ts
index a3f022fb9..78b8cd86d 100644
--- a/src/DatabaseServices/Polyline.ts
+++ b/src/DatabaseServices/Polyline.ts
@@ -243,7 +243,7 @@ export class Polyline extends Curve
     //曲线是否闭合
     get IsClose(): boolean
     {
-        return this.CloseMark || equal(this.StartPoint, this.EndPoint);
+        return this.CloseMark || equal(this.StartPoint, this.EndPoint, 1e-5);
     }
     set CloseMark(v: boolean)
     {
diff --git a/src/Geometry/CurveMap.ts b/src/Geometry/CurveMap.ts
index 71a9c8bda..6c43cb2ea 100644
--- a/src/Geometry/CurveMap.ts
+++ b/src/Geometry/CurveMap.ts
@@ -72,7 +72,7 @@ export class CurveMap
      */
     private GenerateP(v: Vector3): Vector3
     {
-        let str = v.toArray().map(v => v.toFixed(4)).join(",");
+        let str = v.toArray().map(v => v.toFixed(3)).join(",");
         if (this.m_vecMap.has(str))
             return this.m_vecMap.get(str);
         this.m_vecMap.set(str, v);
diff --git a/src/GraphicsSystem/OffsetPolyline.ts b/src/GraphicsSystem/OffsetPolyline.ts
index ba4c768d2..3355babc4 100644
--- a/src/GraphicsSystem/OffsetPolyline.ts
+++ b/src/GraphicsSystem/OffsetPolyline.ts
@@ -1,5 +1,5 @@
 import { Box3, Vector3 } from "three";
-import { arrayLast, arrayRemoveIf, arraySortByNumber } from "../Common/ArrayExt";
+import { arrayLast, arrayRemoveDuplicateBySort, arrayRemoveIf, arraySortByNumber } from "../Common/ArrayExt";
 import { curveLinkGroup, GetPointAtCurveDir } from "../Common/CurveUtils";
 import { FixIndex } from "../Common/Utils";
 import { Arc } from "../DatabaseServices/Arc";
@@ -638,6 +638,7 @@ export class PolyOffsetUtil
                 let iParams = l.IntersectWith(outline, IntersectOption.OnBothOperands)
                     .map(p => l.GetParamAtPoint(p));
                 arraySortByNumber(iParams);
+                arrayRemoveDuplicateBySort(iParams, equaln);
 
                 //需要计算的点列表
                 let needCaclPts: Vector3[] = [];